The present invention relates to a percutaneously applicable preparation containing an antidementia medicament, a percutaneous absorption promoter for an antidementia medicament, or a rectum applicable preparation.
Recently, with an increase in old people, sufferers from dementia such as Alzheimer""s disease have been increasing. Care thereof and the like have been put into social problems. On the other hand, the development of therapeutic medicaments of dementia has rapidly advanced. For example, donepezil hydrochloride has been widely used as a therapeutic medicament for Alzheimer""s disease, from slight to middle degrees, which has acetylcholine esterase inhibiting activity.
Hitherto, in many cases these therapeutic medicaments for dementia have orally been administered in the form of a tablet or the like. As manners for administering a medicament to a patient or the like, there are known percutaneous administration, injection administration, rectum administration and the like, as well as oral administration in the form of a tablet, a capsule, a syrup, a granule, and the like. A suitable manner is selected dependently on the disease thereof and the nature of the medicament.
There may be cases in which it becomes difficult to take an antidementia medicament orally when the condition of dementia gets worse because a dementia patient takes the medicament. Therefore, it is especially useful to administer the medicament percutaneously in the form of an ointment or the like, in the case of a patient whose condition gets worse. However, in general the skin cannot be penetrated by medicaments, and thus it is difficult to cause a sufficiently efficacious amount to be absorbed from the skin into the body. In order to overcome such difficulty, researches have focused on many percutaneous absorption promoters. However, their effects vary dependently on medicaments, and thus it is very difficult to predict percutaneous absorption of a specific medicament from past data.
As an alternative form of administration than oral administration, a rectum applicable preparation can be proposed. The rectum applicable preparation is also called a suppository, and is a preparation that a solid medicament is inserted from the anus to cause the medicament to be absorbed into the rectum. The design for the preparation needs to be conducted considering complex factors such as physical chemistry properties of the medicament, reactivity with a basis, and the like. Thus, it is difficult to produce an optimum rectum applicable preparation by only expansion of the prior art.
The present invention is a percutaneously applicable preparation or a rectum applicable preparation containing an antidementia medicament. The present invention is a percutaneously applicable preparation containing an antidementia medicament, wherein the antidementia medicament is incorporated with a higher alcohol, a lactate of a higher alcohol, an ester of a higher fatty acid and a lower alcohol, or an ester of a fatty acid having 6-18 carbon atoms and propyleneglycol. The present invention is also a percutaneous absorption promoter for an antidementia medicament, which is selected from a higher alcohol, a lactate of a higher alcohol, an ester of a higher fatty acid and a lower alcohol and an ester of a fatty acid having 6-18 carbon atoms and propyleneglycol. Furthermore, the present invention is a rectum applicable preparation containing an antidementia medicament, wherein the antidementia medicament is incorporated with a tiriglyceride of a fatty acid and/or a water-soluble polymer (macromolecule).
The present invention is a method of promoting a percutaneous absorption of an antidementia medicament, which comprises administering the antidementia medicament to a person suffering from dementia either percutaneously or through the rectum, together with at least one selected from a higher alcohol, a lactate of a higher alcohol, an ester of a higher fatty acid and a lower alcohol, and an ester of a fatty acid having 6-18 carbon atoms and propyleneglycol, and use of an antidementia for manufacturing the preparation as defined above.
The antidementia medicament in the present invention means prophylactic agents or preventives and therapeutic agents or remedies for dementia such as cerebrovasular dementia and Alzheimer""s disease. Specific example thereof can include donepezil, TAK-147, CP118954 revastigmine, metrifonate, galanthamine and the like. Donepezil is generally used in the form of donepezil hydrochloride, as a therapeutic agent for Alzheimer""s disease from slight to middle degrees. Chemical name thereof is 1-benzyl-4-(5,6-dimethoxyindanone-2-yl)methylpyperidine. Chemical names of TAK-147 and CP118954 are 3-[1-(phenylmethyl)pyperidine-4-yl]-1-(2,3,4,5-tetrahydro-1H-1-benzazepine-8-yl)-1-propane fumarate, and 5,7-dihydro-3-[2-[1-(phenylmethyl)-4-pyperidinyl]ethyl]-6H-pyrrolo[4,5-f]-1,2-benzisoxazole-6-one maleate, respectively. The structural formulae of these compounds are as follows. 
A higher alcohol in the present invention means a straight chain or branched, saturated or unsaturated alcohol having 10 or more carbon atoms, and can include, for example, decanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol and the like. Moreover, a lactate of a higher alcohol in the present invention is an ester of the above-mentioned higher alcohol and lactic acid, and can include, for example, myristyl lactate, cetyl lactate, lauryl lactate and the like. The ester of a higher fatty acid and a lower alcohol means an ester of a straight chain or branched, saturated or unsaturated fatty acid having 12 or more carbon atoms and a lower alcohol having 3 or less carbon atoms, and can include, for example, diisopropyl adipate, diethyl sebacate, isopropyl myristate, isopropyl palmitate, and the like. Specific examples of esters of a fatty acid having 6-18 carbon atoms and propyleneglycol in the present invention can include propyleneglycol monocaprylate, propyleneglycol monocaproate, propyleneglycol dicaprylate, and the like. It is available as Cefzol (trade name).
Concerning the mixing ratio of the antidementia medicament to such a substance in the present invention, the substance is in an amount of generally 0.1-10 parts by weight, preferably 0.2-5 parts by weight, and more preferably 0.5-3 parts by weight per part by weight of the antidementia medicament.
The dosage form of the percutaneously applicable preparation according to the present invention is not especially limited, if the dosage form makes application to the skin possible. Examples of the dosage form can include an ointment preparation, a creamy preparation, an adhesive preparation, a lotion preparation, and the like.
In order to prepare these dosage forms, any basis material which is generally used can be used. Examples of an oily basis material can include white Vaseline, purified lanoline, squalane, silicone, fluid paraffin, plant oil, waxes and the like. An aqueous basis material may be water, a lower alcohol, a polyhydric alcohol, a water-soluble macromolecule and the like. The adhesive preparation may be a basis material usually used, examples of which can include, as polymer compositions, ones having adhesiveness such as natural rubber, synthetic rubbers, styrene/isoprene/styrene block copolymers, polyacrylate resins, polyisobutylene resins; and soft polyamide resins, polyvinyl alcohols, polyacrylic resins, and the like. Furthermore, a surfactant, a stabilizer, a preservative or the like may be appropriately incorporated, if necessary. In a conventionally used manner, a percutaneously applicable preparation such as an ointment preparation or an adhesive preparation can be produced. The percentage of the medicament in these percutaneously applicable preparations is usually from 0.1 to 5%.
On the other hand, in the case that the present invention is a rectum applicable preparation, it can be produced by dispersing the medicament into an oily basis such as cacao oil or triglyceride of a fatty acid having from a middle chain to a long chain, or a hydrophilic basis such as macrogol, or the like, in a heating and melting manner or the like. The ratio of the antidementia medicament to the basis is not especially limited. However, the weight of a suppository is usually from 1 to 3 g, and the medicament is contained in an amount of from 0.5 to 50 mg. In general, a rectum applicable preparation is also called a suppository, and according to the form thereof, it can also be administrated into the vagina.
The present invention makes it possible to achieve body circulation of an antidementia medicament that is hardly absorbed from the skin by percutaneous administration thereof, and has an especially great advantage for dementia patients who have difficulty in taking any medicament. It is also a preparation which is excellent in safety since administration can be immediately stopped in the case that an undesired effect is revealed. On the other hand, it is said that in the case of a rectum applicable preparation an absorption rate generally becomes lower than that in the case of oral administration. In spite of it, the rectum applicable preparation has exhibited an increased absorption several times as much as the absorption in the case of oral administration, according to a basis.
Next, the effect of the present invention was confirmed by the following method.
An HWY/S1c male rat (hairless rat) having a body weight of about 300 g (9-10 weekly ages) was put under an anesthetic. After it was checked that its skin had no injuries, the whole of the abdominal skin was stripped off. This was cut into suitable sizes, and then the cut pieces were set to a perpendicular type, in-vitro, diffusing cell having a transmission area of 0.785 cm2. At a receiver side, 3 ml of a pH 7.4 phosphoric acid buffer solution were used. At the donor side, a sample solution described in the following was respectively injected in an amount of 3 ml. Stirring was conducted with stirrers at both sides of the receiver and donor. 200 xcexcl of solutions from the solution at the receptor side were respectively sampled at intervals to determine the quantity of donepezil. The determination of the quantity was performed by high-speed liquid chromatography using an ODS column.